Spark plug



DQC. 12, 1939. w p N 5, JR Re. 21,294

SPARK PLUG Original Filed Dec. 12. 1934 AH! .c; E W Z i} 67Z(Z; y

N V j a 67' 277265 Romance. '12, 1939 g 'R ,21,294

UNITED STATES PATENT OFFICE sniffer Y I 9 Original No. 2,097,460, datedNovember 2, 1937, Serial No. 757,206, December 12, 1934. Application forreissue October 30, 1939, Serial No.

9 Claims. (Cl. 123-169) My invention relates generally to spark plugs ofmy invention in a plug of the chambered type; constituting the ignitionmeans of internal comand bustion engines; my invention as to one phaseFigure 4, a view in side elevation of a standard thereoi' relating tospark plugs in general, and as form of spark plug of the unchamberedtype to another phase thereofv to spark plugs of the modified to embodyone of the features of my 5 chambered type, such as for example as showninvention. in U. S. Letters Patent No. 1,797,817, granted to Inaccordance with the particular embodiment Earl E. Bidwell March 24,1931, wherein the of my invention illustrated in Figs. 1 and 2, thespark produced by the plug ignites a relatively plug comprises a. metalshell 5 open at its opposmall charge of the combustion mixture in a siteends at which it is internally and externally 1o chamber'in the plugseparated from, but in threaded, respectively, as represented at 6 andcommunication with, the combustion chamber 1, the internal thread 6being provided to receive of the engine in which the main charge isfired, a threaded gland represented at 8 for a purpose whereby the maincharge is fired by the jet of hereinafter explained and the thread'l'being proflame issuing from the chamber in the plug. vided for-thescrewing of the plug into the usual 15 One of my objects is to provide aconstruction threaded hole provided in the cylinder of an inof sparkplug wherein accurate adjustment of the ternal combustion engine forreceiving a spark electrodes of the plug relative to each other to plug.

produce the proper spacing thereof, one from the J The plug alsocomprises a center, or core, other, may be efiected with ease and greatmember 9 of current-insulating material, as for go facility. exampleporcelain, which seats at its enlarged In connection with another objectof my inannular portion In upon an annular seat II in the ventionandrelating to the chambered type of interior of the shell 5, the core 9being held in spark plug, it may be stated that as these plugs place bythe gland 8.

have hitherto been provided, both of the elec- The lower end II of thecore 9 is of less diam- A trodes are located wholly within the chamberin eter than the space within the shell 5 into which the plug, resultingunder certain conditions of this part of the core extends, the core-endI! use, in the befouling of certain of the electrodes reaching short ofthe bottom of this space, thus by the accumulation thereon of carbonand/or forming, with the shell 5, a chamber l3 into oxide withconsequent impairment of the plug for which, it is designed, a portionof the charge of within the chamber in the plug, and which is chamber ofthe engine to which t p is at lower than that in the main combustionchamber plied, to be fired therein for producing the proof the engine,is not sufficient to maintain the jection of a jet of flame through thelower open electrodes hot enough-to clear them of such beend of thechamber I3 and into the main charge fouling accumulations. in thecombustion chamber of the cylinder to It is my object in this connectionto provide fire the latter, the opening at the lower end of the I aspark plug of the chambered type in which the chamber l3 and which isrestricted as compareo heat generated by the burning fuel in the enginewith the diameter of this chamber, being indishall be utilized to anextent sufilcient to maincated at I 4. The size and shape of the chambertain the electrodes free of carbon and oxide de- [3 and the dimensionsof the opening l4 are posits, thereby to insure the proper functioningof such, as shown, as to cause the spark D1 8 the plug, especially underthe varied conditions operate with the maximum efliciency anddependpresented by different engines. ability in the firing of the maincharge in the Another object is to provide improvements in COmbuStiOhChamber y means of t e jet o flame spark plugs of the chambered type tothe end that Produced the chamber t plu the plug as to its construction,will follow the The electrodes Of this construction are shown lines ingeneral of the standard designs of spark at and the electrode l5 bei gsho'..n as of plugs; d th objects as l b manife t from common form andprovided centrally in the core the following description. 9 with itslower end portion ll projecting part Referring to the accompanying.drawing in Way into the Chamber which I have illustrated my invention asem- The electrode l5 p y, is c ed by e b di d 1' r l dlflerent forms oft t metal shell 5, extends across the lower end of Figure 1 is a view inlongitudinal sectional elethis Shell and has a Portion i h p oje svation of a spark plug of the chambered type and pw ly h ou h h pening4- and into the embodying my invention. chamber ii to a position forproper cooperation Figure 2 is a bottom plan view of the plug of withthe electrode portion l1 to form a suitable Fig. 1. spark gap within thechamber l3.

Figure 3 is a view like Fig. 1 of the lower end Preferably theelectrodes are so proportioned 01 a spark plug constituting anotherembodiment and arranged as shown in Fig. 1 that the elecso 0 functioningdue to the fact that the temperature combustion mixture enters from thecombustion 3 trode portion It extends to a position above the lowerextremity of the electrode portion H as shown by dotted lines in Fig. 1,the electrode portion II extending alongside and lengthwise of theelectrode portion l1 thereby forming a spark gap extending crosswise ofthe plug. The electrode It has a portion represented at l9 which extendscrosswise of the lower end of the shell exterlorly of the chamber l3 andpreferably in suitably spaced relation to the underside of the shell 5as shown, the portion l8 of this electrode which directly cooperateswith the electrode portion I! to form'the spark gap extending upwardlyfrom the portion l9 and through the opening ll into the chamber II.

To provide an electrode Ii having the characteristics above noted, it ispreferred that the electrode be provided of general U-shape as shown andabove referred to, although other shapes may be employed which arearranged to be in good heat conductive relation to the region just belowsaid end wall. The electrode It as shown is supported in position on theshell 5 by the attachment thereof to the shell 5 at the leg portion 20of the electrode, the portion 20 which opposes the leg comprising theelectrode portion l8, being shown as fitted into a downwardly openingsocket 2| in the shell 5.

The provision of the electrode IS with a portion which extendsexteriorly of the chamber l3 and in a position in which it is subjectedto the heat generated by the burning gases in the combustion chamber ofthe engine cylinder, as shown and described, is of great advantage in aconstruction of this kind due to the fact that the electrode Ii becomesthe heating element of the device and objectionable deposits of carbonand scale on the electrodes is avoided, it being understood that eachtime a fresh charge of combustible mixture is introduced into the enginecylinder, (a part of which enters the chamber l3) the electrode l6becomes covered with the combustible mixture and this electrode beingvery hot, complete combustion of the mixture on the electrode iseffected, upon the firing of. the charge, the adaptability of theelectrode I6 for performing as the heating element of the device being 7augmented by reason of its relatively great length as compared with anelectrode located wholly within the chamber of the plug. By theconstruction shown I am thus enabled to utilize the high heat in thecombustion chamber of the engine, and which is considerably higher thanthat which exists in the chamber I! of the plug, for the maintaining ofthe electrodes clear of carbon and oxide deposits.

. Furthermore, as will be understood, the electrode I6 is not onlysubjected to the action of the heat generated by the burning charge,causing it to become heated as stated and minimizing carbonization; butis also subjected to the mechanical force exerted against it by thesurging of the vapor into the plug-chamber and the blasting force of thegases ignited in the plug-chamber and discharged through the opening inthe plug into the combustion chamber, this force serving to blow offaccumulations on the electrode l6 which is directly in the path of theblast.

The spacing of the electrode portion I! from the underside. of the shell5 is of advantage as should there happen to be a tendency toaccumulation of carbon on the electrode It, the danger of suchaccumulation building up to an amount millcient to span the spacebetween the underside of the shell 5 and the electrode It, thusimpairing the operation of'the plug, is avoided.

In accordance with one phase of my invention provision is made foradjusting the electrode 16 relative to the electrode l5 for the pioduction' of the desired length of spark gap.

In accordance with the disclosure in Figs. 1 and 2, the adjustabilityreferred to is provided for by providing such looseness of fit of. theelectrode portion 20 in the socket 2| as to permit the electrode Hi tobe rotated about the portion 20 as an axis, but sufficiently tight' tomaintain the electrode against accidental displacement from adjustedposition, the wall of the opening ll being recessed as represented at 22to provide the desirable clearance between the electrode portion I8 andthe wall of this opening to insure against objectionable bridging bycarbon deposits.

By the arrangement shown it is possible to quckly and accurately adjustthe electrodes for the desired length of spark gap, such adjustment,when the electrodes sidewise lap each other as shown in Figs. 1 and 2,being readily. and easily effected by sliding a suitable gage sticklengthwise through the opening ll into the space between the electrodesI5 and I8.

It will be noted that in the particular construction now being describedthe distance between the electrode portions l8 and 20 is substantiallythe same as that between the electrode portion 20 and the electrodeportion ll, whereby the swinging adjustment of the electrode I6 isparticularly useful in providing for the desired length of spark gap.

Certain features of the invention may be utilized in a construction inwhich the cooperating portions of the electrodes instead of lappingsidewise as in Figs. 1 and 2, extend in endwise spaced relation wherebythe spark gap extends lengthwise of the plug instead of crosswisethereof.

Fig. 3 shows the plugof Figs. 1 and 2 modified in the particular justreferred to and wherein the same numerals are used as in Figs. 1 and 2,the only substantial change being in the provision of the electrodeportion l8 as suiiiciently short to extend in the desired spacedrelation to the electrode portion IT in the direction of the length ofthe plug when the electrode is swung to a position in which theseelectrode portions longitudinally aline.

The electrode adjustment feature as described above in connection withFigs. 1 and 2 may also be utilized in a spark plug of the standard orconventional unchambered type, Fig. 4 showing such a spark plug modifiedto embody this feature of my invention.

As the details of construction of a standard or conventional plug arewell known it is not necessary to describe in detail the plug shown inFig. 4, it being sufficient to state that the threaded metal shellthereof is represented at 23, the porcelain core at 24, the glandholding the core to the shell, at 25, ,and the central electrodeprovided within the core 24, at 26.

The other electrode of this plug, in accordance with the presentinvention is represented at 21 and is preferably of general U-shapeshown, its leg portion 28 extending along the side of the electrode 28as described of the electrode portion 18 in Figs. 1 and 2 and its otherleg portion 29 pivoted in a downwardly opening socket (not shown) in theshell 23 to provide for rotatable adjustment of the electrode 21, asdescribed of the electrode 15 in Figs. 1 and 2.

While I have illustrated and described my invention as embodied inseveral particular forms of construction, I do not wish. to beunderstood as intending to limit it thereto as the same may be variouslymodified and altered and the invention embodied in other forms ofstructure without departing from the spirit oi my invention.

What I claim as new, and desire to secure by Letters Patent, is:

l. A spark plug comprising a shell having a chamber formed therein, awall portion adjacent the end of said plug providing an end wall forsaid chamber, said end wall having an opening formed therein adjacentthe longitudinal center line of the plug, a central electrode extendinginto said chamber, and a substantially U-shaped ground electrodeextending across the outer side of said end wall to adjacent the centralportion of the plug and thence into said chamber to adjacent saidcentral electrode.

2. A spark plug comprising a shell having a chamber formed therein, saidshell having a relatively thin wall portion providing an end wall forsaid chamber adjacent the end of said plug, said wall having an openingformed therein adjacent the longitudinal center line or the plug and ofsubstantially less diameter than the diameter of said chamber, a centralelectrode extending into said chamber, and a substantially U-shapedground electrode extending across a substantial portion of the outerside of said end wall to adjacent the central portion of the plug andthence into said chamber to adjacent said central electrode.

3. A spark plug comprising a shell having a chamber formed therein, saidshell having a transversely extending wall portion adjacent one of itsends providing an end wall for said chamber closely adjacent the end ofsaid plug, said end wall having an opening formed therein adjacent thelongitudinal center line of the plug, a central electrode extending intosaid chamber, and a substantially U-shaped ground electrode extending asubstantial distance across the outer side of said end wall to adjacentthe central portion of the plug and thence into said chamber throughsaid opening and into overlapping relationship with said centralelectrode.

4. A spark plug comprising a shell having a chamber formed therein andproviding side walls for said chamber, a transversely extending wall atone end of said shell providing an end wall for said chamber ofsubstantially lesser thickness than the thickness of said side walls,said end wall having an opening formed therein adjacent the centrallongitudinal line of the plug and'o! substantially lesser diameter thanthe diameter of said chamber, a central electrode extending into saidchamber, and a substantially U-shaped ground electrode extending acrossa substantial portion of the outer side of said end wall to adjacent thecentral portion 01 the plug and thence into said chamber adjacent thecentral portion thereof to adjacent said central electrode.

5. A spark plug comprising a shell having'a chamber formed therein andproviding side walls for said chamber, the inner surface 01 said sidewalls being inclined toward each other and terminating at their lowerends in a transversely extending wall at one end of said shell providingan end wall for said chamber of substantially lesser thickness than thethickness of said side walls, said end wall having an opening formedtherein adjacent the longitudinal center line 0! the plug and orsubstantially lesser diameter than the diameter or said chamber, acentral electrode extending into said chamber, and a ground electrodeextending across a substantial portion of the outer side of said endwall to adjacent the central portion oi the plug and thence into saidchamber adjacent the central portion thereoi and into overlappingrelationship with respect to said. central electrode,

6. A sparl: plug comprising a shell having a chamber formed therein andproviding side walls for said chamber, the inner surface or said sidewalls being inclined toward each other and ter= minating at their lowerends in a transversely ex= tending wall at one end of said shellproviding an end wall for said chamber and of substantially lesserthickness than the thickness of said side walls, said end wall having anopening termed therein substantially concentric with the longl tudinalcenter line of the plug and of substan= tially-lesser diameter than thediameter of said chamber, a central electrode extending into saidchamber, and a ground electrode extending across a substantial portionof the outer side oi said end wall to adjacent the central portion orthe plug and thence inwardly through said opening into said chamberadjacent the central portion thereof and into overlapping substantiallyparallel relationship with respect to said central electrode.

'Z'. A spark. plug comprising a shell having a chamber formed therein, awall portion adjacent the end of said plug providing an end wall forsaid chamber, said end wall having an opening formed therein adjacentthe longitudinal center line of the plug, a central electrode extendinginto said chamber, and a ground electrode ar ranged to be in good heatconductive relation to the region just below said end wall and extendingfrom said shell to adjacent the central portion of said plug and thenceinto said chamber adjacent said central electrode.

8. A spark plug comprising a shell having a chamber formed therein, saidshell having a relatively thin wall portion providing an end wall torsaid chamber adjacent the end of said plug, said wall having an openingformed therein adjacent the longitudinal center line or the plug and 01'substantially less diameter than the diameter of said chamber, a centralelectrode extending into said chamber, and a ground electrode attachedto said shell in good heat conductive relation to the region adjacentsaid end wall and extending to adjacent the central portion of said pluginto said chamber in overlapping relationship with said centralelectrode.

9. A spark plug comprising a shell having a chamber formed therein andproviding side walls for said chamber of substantially lesser thicknessthan the thickness of said side, walls, said end wall having an openingformed therein adjacent the central longitudinal line of the plug and ofsubstantially lesser diameter than the diameter of said chamber, acentral electrode extendin into said chamber, and a ground electrodeattached to said shell in good heat conductive relation to the regionadjacent said end wall, said ground electrode extending across a portionof said end wall opening to adjacent the central portion or the plug andthence within said cham .ber intooverlapping relationship with saidcentral electrode.

WALTER P. m u

